

TUB TELEPHONE. 



of adapting itself to the transmission of variable tones such as those 



of a melody. 



The first suiMiiMsfiil attempt to transmit variable tones by electricity was 

 Mi J T ky pjjijip jfcj^ a teacher in a school at Friedrichsdorf, near Homburg. 

 Oft October SI, 1861, Reis showed his instrument, which he called a telephone, 

 to the Ptmwml Society of Frankfort on the Main. He succeeded in transmitting 

 melodies which were distinctly heard about the room. 



The transmitter of Beis's telephone is essentially a make and break key 

 of so ddint* a construction that the sound-waves in the air are able to 



work it 



The sir vibrations set in motion a stretched membrane like a drumhead, 

 with a piece of platinum fastened to it. This piece of platinum, when vibrating, 

 strikes against another piece of platinum, and so completes the circuit every 

 time contact is made. 



At every point of the circuit there is thus a series of currents corresponding 

 in number to the vibrations of the drumhead, and by causing these to pass 

 through the coil of an electromagnet, the armature of the electromagnet is 

 attracted every time the current passes, and if the armature is attached to a 

 resonator of any kind, the succession of tugs will set it in vibration, and cause 

 it to emit a sound, the pitch of which is the same as that of the note sung 

 into the transmitter at the other end of the line. 



[Mr Cower here played the "March of the Men of Harlech" on the 

 telephone harp placed in the Geological Museum. The instrument consists of 

 a set of steel reeds worked by percussion, which make and break contact on 

 the battery circuit, of which the primary wire of an induction coil forms part. 

 The receivers are worked by the secondary current. There were four receivers, 

 one of them Prof. Bell's original one, placed in different parts of the Senate-house.] 



If the pitch of a sound were the only quality which we are able to 

 distinguish, the problem of telephony would have received its complete solution 

 in the instrument of Reia. But the human ear is so constructed, and we 

 ourselves are so trained by continual practice, that we recognise distinctions 

 in sound of a far more subtle character than that of pitch ; and these finer 

 distinctions have become so much more important for the purposes of human 

 intercourse than the musical distinction of pitch, that many persons can detect 

 the slightest variation in the pronunciation of a word who are comparatively 

 indifferent to the variations of a melody. 



